Pest management practices impact Helicoverpa armigera infestation and foraging behaviour of pollinators in sunflower

Abstract

Field experiments for two consecutive years (2020 and 2021) were conducted to record population dynamics of Helicoverpa armigera Hubner and foraging behaviour of pollinators in sunflower before and after undertaking pest management practices. The study disclosed that H. armigera (larvae) crossed ETL (Economic Threshold Level) from 10th SW (Standard Week), warranting application of pest management measures. Many pollinator species were observed foraging on sunflowers during the same time. The least foraging by pollinators was recorded in early morning and late evening hours, depicting avoidance of insecticide application when pollinator foraging activity is maximum. A combination of synthetic and bio-insecticides (Chlorantraniliprole, Bt-kurstaki, Emamectin-benzoate, Spinosad, Lambda-cyhalothrin, Novaluron, and Neem-oil) were tested for their efficacy against H. armigera and impact on foraging behaviour of pollinators. Bio-insecticide-treated plots recorded significantly higher number of foraging pollinators as compared to synthetic-insecticide-treated plots. Of the insecticides used, Chlorantraniliprole showed highest efficacy against H. armigera but recorded lowest foraging activity of pollinators in both the years of study. In contrast, neem-oil and Bt-kurstaki treated plots showed maximum foraging by pollinators while successfully managing H. armigera.